Heat sealing packaging machine



April 21, 1959 5. J. CAMPBELL HEAT SEALING PACKAGING MACHINE 5Sheets-Sheet 1 Filed Nov. 12, 1954 A I7zm52722 Samue/ J (0 /77 066// AMi M fix I .I i lliu ialivlivfliil li i .J XESEW April 21, 1959 5. J.CAMPBELL 2,882,662

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HEAT SEALING PACKAGING MACHINE I Filed Nov. 12, 1954 5 Sheets-Sheet 5HEAT SEALING PACKAGING MACHINE Samuel J. Campbell, Green Bay, Wis.,assignor to Food Machinery and Chemical Corporation, San Jose, Calif., acorporation of Delaware Application November 12, 1954, Serial No.468,285 6 Claims. (Cl. 53-182) This invention relates to a heat sealingpackaging machine and method. The machine invention represents animprovement on the device of my prior Patent No. 2,682,331.

The machine is of the type in which a continuously moving web ofwrapping material is channeled downwardly about a procession of movingobjects and closed beneath the objects to entube them, the resultingtube of wrapping material being subsequently severed intermediate theentubed objects.

According to the present invention, the wrapping web, after being formedabout the work, has its marginal portions flanged downwardly and theresealed to each other in face to face abutment while the wrapping web andthe entubed work are still within the former. Thereafter, still withinthe former, a multi-ply flange resulting from the sealing operation isfolded over on to the under surface of the wrapping tube. The seal thusmade is subsequently perfect hermetically, being considerably superiorto a heat seal made by simply lapping the margins of the wrapperhorizontally. Thus, when the Wrapping tube is severed intermediatesuccessive work pieces and, desirably, heat sealed transversely at bothsides of the line of severance, a substantially completely sealedpackage results. The invention has been used commercially in wrappingstacks of super-imposed slices of meat products in wax paper.

A further feature of the invention consists in the heating of the entireformer to an accurately controlled temperature such as to facilitate themovement through the former of coated paper without substantial depositsof the coating on the metal of the former.

In the drawings:

Fig. 1 is a diagrammatic view in side elevation of a portion of amachine embodying the invention.

Fig. 2 is a plan view on a materially enlarged scale of the portion ofthe said machine which includes the former for entubing the work piecesin the wrapping web.

Fig. 3 is a fragmentary view in side elevation of a portion of themachine.

Fig. 4 is an enlarged detail view of the former as it appears in sideelevation, other portions of the machine being omitted.

Fig. 5 is a view in cross section taken in section on an enlarged scaleon the line 55 of Fig. 3.

Fig. 6 is a fragmentary detail view in perspective of the delivery endof the former.

Fig. 7 is a fragmentary detail view taken in section on an enlargedscale from the line 7-7 of Fig. 3.

Fig. 8 is a diagrammatic view in perspective fragmentarily illustratingsuccessive steps in the progress of the Web through the former.

Fig. 9 is a view in perspective of the inverted package produced by themachine.

The objects 10 to be wrapped are fed into the machine on the infeedconveyor or conveyors, three of which are used in the instant design asbest shown at 11, 12 and 13 in Fig. 2. For many purposes, a singleinfeed conveyor wide enough to carry the work may be used. In theinstant design, the conveyor 12 is somewhat longer than conveyors 11 and13 to provide added propulsion for the work pieces as they enter theformer 15.

The wrapping web 16 is drawn from a parent roll 17 and passes overappropriate tensioning rolls to the guide roll 18, from which the web 16passes into the former in the general manner shown in Fig. 5 of myPatent 2,682,331.

The former 15 comprises a box-shaped chamber desirably provided adjacentits receiving end with a pair of flaring wings at 19 which projectlaterally from its downwardly inclined margins and assist in guiding theweb 16. The web being considerably wider than the former and beinginitially channeled upwardly. As indicated in Fig. 1, the margins areprogressively turned downwardly and forced beneath the work pieces 10until the work pieces are partially entubed.

In the device of the patent aforesaid, the forming box had bottom wallportions which extended across each other in mutually lappingrelationship to force the side margins of the wrapping web intocorrespondingly lapped positions. In the present device, the former 15is provided, as best shown in Figs. 4, 5 and 8, with bottom wallportions at 20 and 21 which, instead of lapping, are flanged downwardlyat 22 and 23, respectively, to provide a downwardly opening slot at 24into which the side margins 25 and 26 of the wrapping web project intosubstantial face contact. The flanges 22 and 23 of the forming chamberbottom are not continuous but may be relatively short as indicated inFigs. 3 and 4. They have downwardly inclined lower margins as shown at27 in Fig. 4 and then, desirably, they terminate abruptly in thevertical margins 28, to leave the side marginal portions 25 and 26 ofthe web exposed during" the continued advance of the web and the entubedwork pieces.

As the web advances beyond the spaced parallel flanges 22 and 23, itsdepending marginal portions 25 and 26 encounter heat sealing rolls 30and 31 which are best illustrated in Fig. 8. The forming chamber inwhich the web 16 is still held is cut away in Fig. 8 at this point inorder to expose the entubed web and heat sealing roll. The actualmounting and driving connections for the rolls are best shown in Fig. 2and Fig. 3, the latter illustrating one of the heating elements 32. Therolls are desirably, although not necessarily, peripherally ribbed ortoothed at 33 to crimp the heat sealed marginal portions 25 and 26 ofthe wrapper as such portions are laminated together by the heat andpressure of such rolls. A substantially hermetically tight seal isprovided between the marginal portions of the wrapper thus heat sealedtogether in face contact.

During the continued movement of the wrapper through the forming box orchamber 15, the laminated margins of the wrapper, now identified byreference character35, are engaged by a flange 36 projecting laterallyfrom the bottom portion 20 of the forming chamber and lapping beneaththe bottom portion 21 of such chamber as best shown in Figs. 6 and 8.Elongated inclination of the margin 37 of the downwardly offset lappingflange 36 gradually turns the laminated wrapper margins 35 to theposition shown in Fig. 8 and Fig. 9.

Thereafter the continuously moving tubular web and the entubed workpieces therein pass beneath the trans verse crimping and severing rolls38, 39 which are of the general type best disclosed in Figs. 2, 3 and 4of my Patent 2,546,721. These rolls are so timed as to operate upon thetubular wrapper intermediate the entubed work pieces to crimp and heatseal portions of the wrapper Patented Apr. 21, 1959 3 which aretransverse at 40 and 41 (Fig. 9) and to sever the wrapper through theareas thus sealed to produce hermetically sealed packages as shown inFig. 9. Fig. 9 shows the package inverted to illustrate the laminatedmargins 35 of the wrapper as they appear when folded over on the bottomsurface of the work pieces.

Particularly where the wrapper comprises a coated paper such as waxpaper, it is desirable to heat the interior of the former, at leastthroughout the length of that portion of the former about which thepaper is drawn and channeled during the entubing operation. As shown inFigs. 2 to 5,1 provide heating elements 42, 43 supplied with current at44, 45, respectively, and disposed in the upper part of the former abovethe floating pressure plate 4 6 which rests on the wrapper tube and theentubed work pieces. A thermostat shown diagrammatically at 48 projectsinto the former from a point near the discharge end of its heatedsection. It is connected by the wires 49 in controlling relation withthe conductors 44 and 45 leading to the heating element. A suitablecontrol is provided at 50 for thermostat adjustment. The heatingelements within the former keep the metal surfaces traversed by thecoated web at a temperature just sulficiently high so that the coatingson the web become somewhat softened and, in effect, lubricates the metalsurfaces to promote free --web movement. Paraflin and other coatings donot stick to or gum up metal surfaces which are appreciably warmer thanthe coating.

It will be observed that the forming operation is really conducted intwo steps, the heat sealing rolls acting to laminate together theparallel marginal portions of the web after the web has been drawn aboutthe work pieces and before any marginal portion thereof is forced intolapping position beneath the botom of the tube. By performing the heatsealing operation while the flanges are projecting parallel to eachother and in the same downward direction, it is not only possible todraw the web very snugly about the work pieces, but. it is also possibleto seal the web much more tightly than through the use of previouslyknown procedures or apparatus. Particularly when the work pieces arerelatively soft, no great amount of sealing pressure can be exerted onupwardly lapping and oppositely directed margins of the web because suchpressure would necessarily be communicated to the work pieces. Ascompared with the very slight pressure possible under suchcircumstances, I am able to use pressure limited only by the strength ofthe web itself. In the instant device, the requisite pressure isdeveloped by mounting the heat sealing roll 36: on .a slidable bearingblock 52 subject to the adjustable bias of compression springs 53.

Entubed work pieces may be moved from the former in any desired manner.In the device illustrated, I use the lateral belts 55 and 56 asdescribed in my Patent 2,546,721. The driving connections for thevarious parts are illustrated but, so far as the present invention isconcerned, they may be operated in any desired manner. They are morefully described in my two prior patents herein identified.

The device and method herein disclosed may be used to wrap a widevariety of work pieces. They were developed particularly for thewrapping of stacks of sliced meat products under circumstances such thata very tight seal was desired. Accomplishment of such a seal is an easymatter with the apparatus and method disclosed.

While the method has been described incidentally in the course of theforegoing description of the device, it may be summarized as follows:

The wrapping web is pulled through a forming box which first channelsthe web by turning its margins progressively downwardly about asuccession of mutually spaced work pieces fed into the box beneath theweb. As the forming operation continues during the progressive advanceof the'web and the workpieces, the web is folded beneath the work pieceswith its free margins turned downwardly at a point centrally beneath theadvancing work pieces.

Thereupon the free margins of the web are exposed, being substantiallyin face contact and both projecting in the same downward direction.During the continued ad- Vance of the web and the partially wrapped workpieces, the margins are sealed to each other, desirably by laminatingheat and pressure, although, in the generic aspects of the method, anyother sealing or connecting means may be employed at this point.

Thereafter, during continued movement of the web and the now enclosedwork pieces, and desirably while the web is still tightly encased in theforming chamber, the connected 0r laminated margins are folded over uponthe lower face of the resulting tube to complete the entubing of thework pieces, after which the tube is severed intermediate successivework pieces and is transversely heat sealed along the margin ofseverance to provide a wrapper in which each work piece is substantiallyhermetically sealed.

I claim:

1. A former for a wrapping machine, comprising two substantiallyhorizontal wall portions adapted to support work pieces during wrappingthereof, said wall portions being laterally spaced one from the other toprovide a longitudinally extending slot therebetween, said slot beingadapted to receive side marginal portions of a web of wrapping material,a pair of parallel longitudinally extending spaced apart flangesprojecting downwardly from the side edges of said slot respectively, apair of heat sealing members located at opposite sides of said slotrespectively and aligned with said pair of downwardly projectingflanges, and pressure means laterally urging at least one of said heatsealing members toward the other of said members.

2. A former for a wrapping machine, comprising two substantiallyhorizontal wall portions adapted to support work pieces during wrappingthereof, said wall portions being laterally spaced one from the other toprovide a longitudinally extending slot therebetween, said slot beingadapted to receive side marginal portions of a web of wrapping material,a pair of parallel longitudinally extending spaced apart flangesprojecting downwardly from the side edges of said slot respectively, apair of heat sealing members located at opposite sides of said slotrespectively and aligned with said pair of downwardly projectingflanges, at least one of said members being movable with respect to theother member, and pressure means laterally urging said movable membertoward said other member.

3. A former for a wrapping machine, comprising two substantiallyhorizontal wall portions adapted to support work pieces during wrappingthereof, said wall portions being laterally spaced one from the other toprovide a longitudinally extending slot therebetween, said slot beingadapted to receive side marginal portions of a web of wrapping material,a pair of parallel longitudinally extending spaced apart flangesprojecting downwardly from the side edges of said slot respectively, apair of heat sealing rollers located at opposite sides of said slotrespectively and aligned with said pair of downwardly projectingflanges, at least one of said rollers being mounted for movement withrespect to the other roller, and spring means laterally pressing saidmovable roller toward said other roller.

4. A former for a wrapping machine, comprising two substantiallyhorizontal wall portions adapted to support Work pieces during wrappingthereof, said wall portions being laterally spaced one from the other toprovide a longitudinally extending slot therebetween, said slot beingadapted to receive side marginal portions of a web of wrapping material,a pair of parallel longitudinally extending spaced apart flangesprojecting downwardly from the side edges of said slot respectively, apair of heat sealing rollers located at opposite sides of said slotrespectively and adjacent said pair of downwardly projecting flanges, abearing block for one of said rollers, said bearing block being movabletoward the other said roller, and spring means biasing said bearingblock toward said other roller, whereby said one roller is urged towardthe other said roller under positive lateral pressure.

5. A former for a Wrapping machine, comprising two substantiallyhorizontal wall portions adapted to support work pieces during wrappingthereof, said wall portions being laterally spaced one from the other toprovide a longitudinally extending slot therebetween, said slot beingadapted to receive side marginal portions of a web of wrapping material,a pair of parallel longitudinally extending spaced apart flangesprojecting downwardly from the side edges of said slot respectively, apair of heat sealing members located at opposite sides of said slotrespectively and aligned with said pair of downwardly projectingflanges, and a folding flange adjacent said heat sealing members on theside thereof opposite said downwardly projecting flanges, said foldingflange merging at one side with one of said Wall portions, and beingdownwardly ofiset and extending beneath the other of said wall portions.

6. Apparatus for wrapping articles, comprising conveyor means forcontinuously advancing an article to be Wrapped, means for continuouslyadvancing a Web of wrapping material toward said article, a formeradapted to shape the Web of wrapping material progressively about thetop, sides and bottom of the article, said former being provided withmeans for turning downwardly beneath the article the opposed marginalside portions of the web of wrapping material, means for sealingtogether the downwardly turned web side portions, and means for foldingthe sealed web side portions upwardly toward the undersurface of thewrapped article.

References Cited in the file of this patent UNITED STATES PATENTS2,018,806 Richard Oct. 29, 1935 2,142,505 Gammeter Jan. 3, 19392,218,585 Merkle Oct. 22, 1940 2,331,927 Palmer Oct. 19, 1943 2,422,188Epstein June 17, 1947 2,555,758 Noble et al June 5, 1951 2,602,276Campbell July 8, 1952 2,762,178 Campbell Sept. 11, 1956 Disclaimer2,882,662.-Samuel J. Campbell, Green Bay, WVis. HEAT SEALING PACK- AGINGMACHINE. Patent dated Apr. 21, 1959. Disclaimer filed July 28, 1967, bythe assignee, FMU Corpomtz'on. Hereby enters this disclaimer to claim 6of said patent.

[Oficz'al Gazette October 3, 1967.]

